The 4200 Series shocks use AST’s Twin Piston Dual Adjust (TPDA) technology. Similar non adjustable versions have been found in the highest forms of racing. TPDA builds on this technology to allow for 2 adjustment knobs to be mounted on the shock body (no tools required). Quick rebound and compression changes can be made in the pits in seconds. 4200s are fully customizable and rebuildable.

AST-USA offers full rebuilding and revalving services for AST shocks at competitive prices. This includes quick turn around when you need it the most.
Benefits include:
Monotube design - gives the biggest piston sizes available
Floating piston design with high pressure nitrogen means no cavitation around the piston
Compression and Rebound adjuster knobs permanently mounted on the dampers – no fumbling for knobs
Fully threaded strut bodies allow maximum tire width without fender rolling or larger spacers
Rebuildable by AST-USA – get the valving you want, when you want it.
AST-USA offers full rebuilding and revalving services for AST shocks at competitive prices. This includes quick turn around when you need it the most.

HP, how does this ride vs. stock? I'm considering AST but I don't want to lose a lot of the ride quality on the street. I race so I don't intend on tracking this car much. Mind telling me/us what the spring rates are?

Any word as if the 1m and m3 are
The same fitments?? Do you have the ast kits in stock?

4100s are in stock.

4200s are custum built and takes 6 weeks.

Quote:

Originally Posted by Dan Parker

They are the same.

HP, how does this ride vs. stock? I'm considering AST but I don't want to lose a lot of the ride quality on the street. I race so I don't intend on tracking this car much. Mind telling me/us what the spring rates are?

With proper spring rates the AST ride is about the same as stock but with more control. Damping force is generated very quickly with the ASTs and you can get away with slightly lower spring rates for comfort.

Spring rates will be tailored to each individual. You can also see the rates stamped right on the springs in the photo.